For example, in order to observe defects, impurities and the like of the interior of a semiconductor device, a cross-section for observation is obtained by subjecting a sample to etching processing by using a focused ion beam (FIB) apparatus. As such a method, a technology known as “cut and see” in which the cross-section processing and observation are repeatedly performed is known (for example, see JP-A-H11-273613 and JP-A-H11-273936). Cut and see uses an FIB-SEM apparatus in which a scanning electron microscope (SEM) column is mounted to an FIB apparatus, and is executed by repeating the cross-section processing with the FIB apparatus and acquiring of SEM images of the cross-sections. By combining the plurality of acquired cross-sectional SEM images, it is possible to construct a three-dimensional image of the interior of the sample.
Here, the cross-sectional SEM image is generated by detecting secondary electrons that are emitted by irradiating the cross-section of the sample with a charged particle beam from the SEM column.
Incidentally, characteristic X-rays are emitted in addition to the above-described secondary electrons when an electron beam is emitted from the SEM column to the cross-section of the sample. It is possible to generate an elemental analysis image of the cross-section by detecting the X-rays. This is referred to as energy dispersive X-ray spectrometry (EDS or EDX). Accordingly, by applying the cut and see method to EDS, it is possible to construct a three-dimensional element distribution of the interior of a sample.